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.\" Author: Archie Cobbs <archie@FreeBSD.org>
.\" $Whistle: ng_lmi.8,v 1.4 1999/01/25 23:46:27 archie Exp $
.\"
.Dd November 13, 2012
.Dt NG_LMI 4
.Os
.Sh NAME
.Nm ng_lmi
.Nd frame relay LMI protocol netgraph node type
.Sh SYNOPSIS
.In sys/types.h
.In netgraph/ng_lmi.h
.Sh DESCRIPTION
The
.Nm lmi
node type performs the frame relay LMI protocol.
It supports
the ITU Annex A, ANSI Annex D, and Group-of-four LMI types.
It also supports auto-detection of the LMI type.
.Pp
To enable a specific LMI type, connect the corresponding hook
.Dv ( annexA ,
.Dv annexD ,
or
.Dv group4 ")"
to DLCI 0 or 1023 of a
.Xr ng_frame_relay 4
node.
Typically, Annex A and Annex D live on DLCI 0 while Group-of-four
lives on DLCI 1023.
.Pp
To enable LMI type auto-detection, connect the
.Dv auto0
hook to DLCI 0 and the
.Dv auto1023
hook to DLCI 1023.
The node will attempt to automatically determine
which LMI type is running at the switch, and go into that mode.
.Pp
Only one fixed LMI type, or auto-detection, can be active at any given time.
.Pp
The
.Dv NGM_LMI_GET_STATUS
control message can be used at any time to query the current status
of the LMI protocol and each DLCI channel.
This node also supports the
.Dv NGM_TEXT_STATUS
control message.
.Sh HOOKS
This node type supports the following hooks:
.Bl -tag -width ".Va auto1023"
.It Va annexA
ITU Annex A LMI hook.
.It Va annexD
ANSI Annex D LMI hook.
.It Va group4
Group-of-four LMI hook.
.It Va auto0
Auto-detection hook for DLCI 0.
.It Va auto1023
Auto-detection hook for DLCI 1023.
.El
.Sh CONTROL MESSAGES
This node type supports the generic control messages, plus the following:
.Bl -tag -width foo
.It Dv NGM_LMI_GET_STATUS
This command returns status information in a
.Dv "struct nglmistat" :
.Bd -literal -offset 4n
#define NGM_LMI_STAT_ARYSIZE   (1024/8)

struct nglmistat {
  u_char  proto[12];	/* Active proto (same as hook name) */
  u_char  hook[12];	/* Active hook */
  u_char  fixed;	/* If set to fixed LMI mode */
  u_char  autod;	/* If currently auto-detecting */
  u_char  seen[NGM_LMI_STAT_ARYSIZE];	/* DLCIs ever seen */
  u_char  up[NGM_LMI_STAT_ARYSIZE];	/* DLCIs currently up */
};
.Ed
.It Dv NGM_TEXT_STATUS
This generic message returns is a human-readable version of the node status.
.El
.Sh SHUTDOWN
This node shuts down upon receipt of a
.Dv NGM_SHUTDOWN
control message, or when all hooks have been disconnected.
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr ng_frame_relay 4 ,
.Xr ngctl 8
.Rs
.%T "ANSI T1.617-1991 Annex D"
.Re
.Rs
.%T "ITU-T Q.933 Digital Subscriber Signaling System No. 1 - Signaling Specification for Frame Mode Basic Call Control, Annex A"
.Re
.Sh HISTORY
The
.Nm
node type was implemented in
.Fx 4.0 .
.Sh AUTHORS
.An Julian Elischer Aq Mt julian@FreeBSD.org
